Shifts in salamander body size associated with 60 years of climate change

Climate change impacts body size, a fundamental trait central to
energetics and reproductive success. Most studies on body size shifts in
response to climate change have focused on temperature, with smaller sizes
expected under warming. However, precipitation has received less attention
even though water and heat balance interact to impact body size.
Precipitation changes may be particularly important for wet-skinned
amphibians. We examined body size shifts in 10 plethodontid salamander
species in the Balsam Mountains, Virginia, USA. Using historical data
(1957-1959) as a baseline, we resurveyed salamanders (2021 and 2023) to
assess how temperature and precipitation shifts have influenced body size.
We hypothesized warmer, wetter conditions would reduce body sizes across
species. Over 60 years, temperatures warmed across elevation, while
precipitation increased more at higher compared to lower elevations. After
accounting for phylogeny, warming generally reduced body size, with
temperature effects amplified by increased precipitation at high
elevations. However, the direction and magnitude of body size shifts were
species-specific indicating that size shifts are a complex interplay of
environmental factors and species traits. Our findings highlight the
importance of considering interacting climate variables when assessing
responses to environmental change, particularly in montane
ecosystems.